Contact model for the prediction of NMR N-H order parameters in globular proteins

An analytical relationship is presented for the estimation of NMR S2 order parameters of N-HN vectors of the protein backbone from high-resolution protein structures. The relationship solely depends on close contacts of the peptide plane to the rest of the protein. Application of the relationship to a number of proteins with high-resolution X-ray and NMR structures yields S2 values that are in good agreement with the ones determined from experimental relaxation data.